Water level drop at outlet InterFoam solver
 

Hi all,

I have some problems using the interfoam solver for my free surface flow through a pipe (which is completely under water) from one water basin to another water basin. I am fairly new to OpenFOAM, so I hope somebody can help me here :) At first, there is not much of a problem, but after some time the water in the second water basin starts to drop. I think that it must have something to do with the outlet boundary conditions. In my case, I am looking for the steady state solution of this flow to calculate some important properties in hydraulic structures.

I already have tried a bunch of boundary conditions which seems logical to me, but the problem still occurs (Sometimes only after 90 seconds). I also splitted the outlet boundary in an air and water outlet boundary because of this, but even that eventually doesn't solve it. These are my latest settings;

inlet:
U: variableHeightFlowRateInletVelocity
p_rgh: fixedFluxPressure 0
alpha: variableHeightFlowRate

outlet_air:
U: fixedValue (0 0.1 0), To avoid air coming in to the model that will push the water down.
p_rgh: fixedFluxPressure 0
alpha: inletOutlet 0

outlet_water:
U: inletOutlet, inletValue: uniform (0 0 0), value: $internalfield
p_rgh: fixedFluxPressure 0
alpha: inletOutlet 1

atmosphere:
U: zeroGradient
p_rgh: totalPressure uniform 0
alpha: inletOutlet 0

Here are some pictures so you can see what happens after a while:
https://imgur.com/a/AL8uPcE
Note that water flows in the Y direction.

Hope somebody could help me out!

Cheers

Hi!

I have the same problem. Did you solved it somehow?

Thank you!

Péter